index / prev / next

< Leaf Spring Set And All >

[Milling Power Feeder]

I made a simple power feeder of the milling machine with only one axis and constant speed, utilizing AC 6W small motor with a speed reduced to 10RPM by a gearhead. It was connected to X-axle of the milling table with a coupling sleeve.

The sleeve can slide along the motor axle, but bound in circular direction by a groove and a pin. When not in use, you withdraw the sleeve towards the motor, then a crossing bar drops between the sleeve and X-axle. And you can rotate X-axle freely with a handle at another end of the X-axle.

If you pull up the crossing bar, a coil spring pushes the sleeve against X-axle. You turn on the motor, then the sleeve and X-axle are bound by two pairs of pins and notches, and X-axle starts rotating.

I also prepared auto-stop function with a small emergency bottom. A steel bar fixed on the base pushes the bottom fixed on the moving stage at desired position. Both the steel bar and the bottom can be fixed at any position and direction.

[Truing up of the main frame]

The main frames had a slight warp. It deviated 3mm from the true straight line at middle of the frames. I designed the chassis assembly strictly so as to clear 7.5 meter radius track, so 3mm deviation cannot be ignored. Therefore I tried to true up the frames. Mount two steel blocks at both ends of 1 meter long steel bar. Bridge the frame between the blocks. Then squeeze the frame and the steel bar together at midpoint of them with 2.5 ton large clamper. I controlled both squeezing level and deviation change by a height gauge. Finally I got less than 1mm deviation by squeezing more than 30mm.

Incidentally, I employ 1 meter steel ruler as 'straight edge'. You can confirm straightness of your ruler as follows. Confirm that the width of the ruler is uniform in any position. Scribe a long line with one edge of the rule. Reverse the ruler and fit another edge to the scribed line.

[Main frame cutting]

I modified design of the main frame. But it had already laser-cut, so I have to do additional work by myself. Separating surplus metal by drilling in array, then I finished them with files and mills.

Main frame rear end was cut to a half thickness so as to attach the rear frame. It was a hard work to cut 6mm depth in large area. I employed rough-cut end mill and power-feed for the work.

[Leaf spring set]

It is terrible work to prepare functional leaf spring for each wheels. Because, for my engine, it needs 148 of bent plates and almost of the plates have octagonal profile. Full scale locomotive has steel leaf spring. But steel is too strong for scaled down locomotive. So I employed phosphor bronze plates for them.

I asked a machining factory to shear a large phosphor bronze sheet to 12mm width strip, and to bend them in a desired radius. The photo shows package of the strips from the factory.

The strip was cut by a hacksaw,then, so as to finish in a shape, I made a milling jig to hold 6 plates in a time. The rotary table is not for cutting radius, but to rotate the job at an angle of 45 degrees. After milling, holes for binding and linkage were drilled with the same setup.

Finished spring plates. I managed a lot of plates in different length like that.

The leaf spring holders were made from laser-cut steel strip. The picture shows a bending jig with and without job, made from steel scrap. Note the slit in front face of the jig, in which once-bent strip is inserted. Then whole job is clamped in a vise firmly, and second bending is done. Although the strip was pre-annealed by a propane torch, hard hammering was needed to get a sharp 'U' shape.

Assembled leaf spring. From the top, leading wheel's spring, driving wheel's spring and trailing wheel's spring. It needs 10 sets in all. Note the 4th plate from top has half round notch at each end, so as to clear linkage shafts.

In the last month, I joined 'Mini-SL Festa in Fukuchiyama', one of the biggest live steam meets in Japan. 90 locomotives were running at 700 meters endless track.

Also in this month, I joined a meet in Akubi Lightweight Railway, a garden railway produced by a famous Japanese mystery writer Hiroshi Mori. The loco I drive is 'Shay' built by a Japanese model engineer Yoshinori Kiuchi.

index / prev / next